Electric circuit breaker



Nov. 14, 1950 A. PlPPONZl ELECTRIC CIRCUIT BREAKER 2 Sheets-Sheet 1 Filed April 3, 1946 A. PlPPONZl ELECTRIC CIRCUIT BREAKER Nov, 14, 1950 2 Sheets-Sheet 2 Fig.4

Filed April 3, 1946 Fig.2

We 'CZ' M a Patented Nov. 14, 1950 UNITED STATES PATENT OFFICE Application April 3, 1946, Serial No. 659,195 In Italy April 21,- 1945 V The present invention relates to an automatic circuit breaker, and more particularly to circuit breakers for low voltages.

It is an object of the present invention to provide an electric circuit breaker in which the contacts have a sufliciently high opening speed.

It is another object of the present invention to provide a circuit breaker having a lever system for operating the contacts which is designed so that the lever system does not reach a dead center position even when it is locked in the position corresponding to the maximum eifort.

An automatic circuit breaker according to the invention comprises in combination at least two fixed contacts, a bridging contact member adapted to connect the fixed contacts, a movable contact support member carrying the bridging contact member movably between contact making position in contact with the fixed contacts and contact breaking position spaced from the fixed 0011-. tacts, spring means tending to move the movable contact support member together with the bridging contact member from operative into inoperative position of the same, a first toggle lever turnably secured at one end to the movable contact support member; a second togglelever turnably secured at one end to the first toggle lever at a point spaced from that point at which the first toggle lever is secured to the movable contact support member, an operating double -armed lever arranged turnably about a stationary pivot andmanually operable b turning of one of its lever arms, pivoting means turnablysecuring the second toggle lever at its other end to the other lever arm of the operating double-armed lever, a catch projection provided on one of the toggle levers, a holding double-armed lever turnably pivoted about pivoting means, a catch hook on one end of one-lever arm of the holding double-armed lever adapted to engage the catch projection provided on one of the toggle levers only when the bridging contact member is in operative position, stop means provided on the same lever arm of the holding double-armed lever as the catch hook and associated with the same so as to prevent turning of the toggle levers into and beyond aligned position, and electromagnetic operating means for turning the lever means so as to release the catch means, permitting the toggle levers together with the movable contact support member and the bridging contact member to be moved by action of the spring means from operative into inoperative position of the bridging contact member. The novel features which I consider as characteristic for my invention are set forth in par;-

Claims. (01. Zoo-406) ticular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view of a four-pole breaker according to the invention.

Fig. 2 is a detailed View, partially in section, of the mechanical and electromagnetic device for the breaker operation;

Fig. 3 is a detail showing a way of assembling the movable contacts.

Fig. 4 is a modification of the magnetic operator which includes a thermal opera-tor.

Referring now to the drawing and first to Fig. 1, the breaker illustrated comprises stationary contacts I and l, to which are fastened the ends of the leads to beconnected. Contacts l and I can be bridged b movable bridging contact members 2, carried by a movable contact support such as a single bar 3, provided with insulating blocks 3, the bar 3 is moved by a lever system 4, 5, 6 operated by hand or by an electromagnet acting on the rear portion 6' of lever 6 (Fig. 2) Said lever system. includes, as principal members, the two toggle levers 4 and 5, hinged together on a pivot M, so as to constitute a toggle, and pivoted at their other ends, lever 4 on piece 1 carryingthe bar 3 supporting the movable contacts 2, and lever 5, by means of pivot [9, to an arm 20 of a double-armed lever 20, 25, pivoted in its turn at 2 I, to a stationarypart of the device.

Combined with the togglelevers 4 and 5, is a double -armed lever 6, also pivoted to pivot i9, and ending at one end-with a catch-hook or latch .6" destinedto mesh the end or catch-projection 4 of levert. At its opposite end, double-armed lever 6 is free, and its rear portion 5 is subjected to the action of the movable plunger 23 of an electromagnet 24.

As it appears clearly from the drawing, which represents the breaker in the closed position, the

two toggle levers 4 and 5, are not aligned, or

in dead centreposition, but they are locked in this position by the catch hook 6" of lever 6. The collapse of the toggle lever system around pivot I4 will take place with a minimum effort, since the toggle system has the tendency to bend further by reaction of a spring 8, which intervenes as soon as lever 4 is set free by the catch hook 6" owing to asmall rotation of lever 6 around pivot I9, which also calls for a minim m effort. Lever 6. moreover is provided in to open the circuit, coil 24 will automatically.

become suificiently energized, thereby attracting plunger 23 and causing same to strike against the lower free end of lever B, so that same will revolve about pivot 19, disengaging latch 6" from lever 4, and delivering to same a blow which helps the desired displacement under the action of spring 8. Thus contact 2 moves away from stationary contacts l and I, thereby opening the respective circuit.

Piece 1 ends in a shank 9 provided with an external thread 9, on which is screwed a nut H],

which strikes in the opening motion against the bar 3 supporting the movable contacts 2. The impact of nut l0 against bar 3 takes place when the assembly is already in motion and has acquired a considerable speed, so that the contacts open very quickly.

In consequence thereof the breaker has a very high interrupting power owing to the rapidity with which the toggle'levers 4 and 5 trip, since, even in latched condition, they are never in dead centre position, and owing to the characteristics of spring 8, and above all owing to the fact that the element which moves the bar 3 does not start, when the motion of bar 3 begins, from standstill, but has already acquired a considerable speed.

According to another embodiment of the electromagnetic device (Fig. 4) a thin copper jacket 26 is surrounding plunger 23 and provided with an extension 26,'on which is fixed a bimetallic strip 2'! which, in deflected condition, acts on an extension 28v of lever B provoking the tripping of the assembly of levers 6, .4 and 5, and therefore the opening of the breaker, even in case of not excessive, but prolongated overloads. Thus, coil 24 will have only a few turns, being intended to operate only in case of severe overloads. The

current flowing through coil 24 heats the coil which, by means of jacket 26 and extension 26' transmits the heat to the bimetallic element 21.

The bimetal, by its bending, acts on extension 28 of lever B, and causes same to turn about its pivot l9 and to unhook from end 4' of lever 4, thereby allowing spring 8 to open'the breaker.

The opening of the breaker on not excessive but prolonged overloads may be obtained also by properly proportioning coil 2 so that under current intensities too high for a prolonged operation, plunger 23 acts on tail 6' with weak shocks, which however, if repeated, result in the opening of the switch. I

In order to closethe breaker, hand operationis provided by means of lever 25. a

Another characteristic of the present invention is the non rigid suspension system of the insulating blocks 3, carrying the contacts 2 shown in Fig. 3. Block 3 .carrying the movable contacts 2, is mounted on bar 3, by means of member 15 provided at the top with a narrow and long head i5 and connected at its lower side to bar 3, by means of a simple pin l6 which allows relative large movements of block 3' with respect to bar 3. I p

, In the'closing operation of the contacts 2, bar 3, is lowered and pulls piece I5, owingto pin i6,

down. In itsturn piece [5 bymeans of its head l5 bears against block 3 on which are fixed the contacts 2 but owing to the fact that piece l5 can oscillate with respect to block 3, a relative rotational movement takes place between member l5 and 3, i. e. a rotation of the insulating block 3 about an axis parallel to the longer side of the head i5 of piece I5.

This loose suspension insures a uniform closing pressure distribution on all contacts even if stationary contacts should not all be exactly aligned on a same plane.

Further, for each pole, the circuit is interrupted at two points, not simultaneously in consequence of the loose suspension described above, so that,

' when the second contact opens, any tendency of the are formed on the first contact to persist, stops at once. The breaker may be double-pole or three-pole, or have any desired number of poles. In case the pole number is odd, it may be preferable to dispose the contacts evenly distributed around the center of a circular or polygonal plate replacing bar 3.

The movable contacts may be provided with auxiliary contacts in order to avoid burning of the seats of the main contacts and be combined with are breaking systems comprising an iron strip shaped so as to screen the main contacts and to compel the arc to travel away from the contacts.

The operating system and other characteristic dispositions objects of the present invention, are suitable for a very wide line of breakers, from telephone applications to the circuit-breakers for any low voltage power distributing system.

Of course, the form and dimensions of the difierent parts as well as all constructive details may vary according to necessities without therefore coming out of the scope of the present invention.

What I claim is:

1. An automatic circuit breaker comprising in combination at least two fixed contacts; a bridging contact member adapted to connect said fixed contacts; a movable contact support member carrying said bridging contact member movably between contact making position in contact with said fixed contacts and contact breaking position spaced from said fixed contacts; spring means tending to move said movable contact support member together with said bridging contact member from operative into inoperative position of the same; a first toggle lever turnably secured at one end to said movable contact support member a second toggle lever turnably secured at one end to said first toggle lever at a point spaced from, that point at which said first toggle lever .is secured to said movable contact support member; an operating double-armed lever arranged turnably about a stationary pivot and manually operableby turning of one of its lever arms; pivoting means turnably securing said second toggle lever at its other end to the other lever arm of said operating double-armed lever; a catch projection provided on one of said toggle levers; a holding double-armed lever turnably pivoted about pivoting means; a. catch hook on one end of one lever arm of said holding doublearmed lever adapted to engage said catch projection provided on one of the toggle levers only when saidbridging contact member is in operative position; stop means provided on the same leverI arm of said holding double-armed lever as said catch hook andassociated with the same so as to prevent turning of said toggle levers into and beyond aligned position; and electro-ma g- "said fixed contacts and contact breaking position spaced from said fixed contacts; spring-means tending to move said movable contact support member-together with said bridging contact member from operative into inoperative position of the same; a first toggle lever turnably secured at one end to said movable contact support member; a second toggle lever turnably secured at one end to said first toggle lever at a point spaced from that point at which said first toggle lever is secured to said movable contact supportljmemher; an operating double-armed lever arranged l turnably about a stationary pivot and manually operable by turning of one of its lever arms; pivoting means turnably securing said second toggle lever at its other end to the other lever arm of said operating double-armed lever; a catch projection provided on one of said toggle levers; a holding double-armed lever; attaching means turnably pivoting said holding double-armed lever to said other lever arm of said operating doublearmed lever; a catch hook on one end of one lever arm of said holding double-armed lever adapted to engage said catch projection provided on one of said toggle levers only when said bridging contact member is in operative position; and electromagnetic operating means for turning said holding double-armed lever about said pivoting means that said catch hook releases said catch projection permitting said toggle levers together with said movable contact support member and said bridging contact member to be moved by action of said spring means from operative into inoperative position of said bridging contact member.

3. An automatic circuit breaker comprising in combination at least two fixed contacts; a bridging contact member adapted to connect said fixed contacts; a movable contact support member carrying said bridging contact member movably between contact making position in contact with said fixed contacts and contact breaking position spaced from said fixed contacts; spring means tending to move said movable contact support member together with said bridging contact member from operative into inoperative position of the same; a first toggle lever turnably secured at one end to said movable contact support member; a second toggle lever turnably secured at one end to said first toggle lever at a point, spaced from that point at which said first toggle lever is'se cured to said movable contact support member; an operating double-armed lever arranged turn,- ably about a stationary pivot and manually operable by turning of one of its lever arms; pivoting means turnably securing said second toggle lever at its other end to the other lever arm of said operating double-armed lever; a catch projection provided on one of said toggle levers; a holding double-armed lever; attaching means turnably pivoting said holding doublearmed lever to said other lever arm of said operating double-armed lever; a catch hook on one end of one lever arm of said holding double-armeddever adapted-to engage said catch projection provided on one'of the toggle levers only when said bridging'contact member is in operative position; stop means provided on the same lever arm of saidholdi ngdou ble-armed lever as said catch hook and associated with the same so as toprevent turning of said toggle levers into and'beyond aligned position; and electro-magnetic operating-means for turning-said lever means so as to release said catch means, permitting said toggle levers together with said movable contact support member and said bridging contact member tobe moved by action of said spring means from operative into inoperative position of said bridging contact member.

4. 'An automatic circuit break comprising-in combination at least two fixed contacts; "a bridging contact member adapted to connect said fixed contacts; a -movable contact support member carrying said bridging "-cont'actmem' ber movably between contact making position in contact with said fixed contacts'and contact breaking position spaced from said fixed contacts; spring means tending to move said movablecontact support member together with said bridging contact member from operative into inoperative position of the same; a first toggle member turnably secured at one end to said movable contact member; a second toggle lever turnably secured at one end to said first toggle member at a point spaced from that point at which said first toggle lever is secured to said movable contact support member; an operating double-armed lever arranged turnably about a stationary pivot and manually operable by turning of one of its lever arms; pivoting means turnably securing said second toggle lever at its other end to the other lever arm of said operating double-armed lever; a catch projection provided on said first toggle 1ever at the other end of the same; a holding double-armed lever; attaching means turnably pivoting said holding double-armed lever to said other lever arm of said operating double-armed lever; a catch hook on one end of one lever arm of said holding double-armed lever adapted to engage said catch projection provided on one of the toggle levers only when said bridging contact member is in operative position; stop means provided on the same lever arm of said holding .double-armed lever as said catch hook and associated with the same so as to prevent turning of said toggle levers into and beyond aligned position; and electro-magnetic operating means for turning said lever means so as to release said catch means, permitting said toggle levers together with said movable contact support member and said bridging contact member to be moved by action of said spring means from operative into inoperative position of said bridging contact member.

5. An automatic circuit breaker comprising in combination at least two fixed contacts; a bridging contact member adapted to connect said fixed contacts; a movable contact support member carrying said bridging contact member mounted thereon movably between contact making position in contact with said fixed contacts and contact breaking position spaced from said fixed contacts; spring means tending to move said movable contact support member together with said bridging contact member from operative into inoperative position of the same; a first toggle member turnably secured at one end to said movable contact support member; a second toggle lever turnably secured at one end to said first toggle member-at a point spaced from that point at which said first toggle lever is secured to said movable contact support member; an operating doublearmed lever arranged turnably about a stationary pivot and manually operable by turning of one of its lever arms; pivoting means turnably securing said second toggle lever at its other end to the other lever arm of said operating double-armed lever; a catch projection provided on said first toggle lever at the other end of the same; a holdingdouble-armed lever; attaching means turnably pivoting said holding double-armed lever to said other lever arm of said operating doublearmed lever; catch hook on one end of one lever arm of said holding double-armed lever adapted to engage said catch projection provided on one of the toggle levers only when said bridging contact member is in operative position; stop means provided on the same lever arm of said holding double-armed lever as said catch hook and associated with the same so as to prevent turning of s aid toggle levers into and beyond aligned position; and electro-magnetic operating means for turning said lever means so as to release said catch means, permitting said toggle levers together with said movable contact support member and said bridging contactmember to be moved by action of said spring means from operative into inoperative positionvof said brid ing contact member.

ADRIANO PIPPONZI.

REFERENCES CITED I The following references are of record in the file of this patent:

UNITED STATES PATENTS 

